+ * This class provides common implementations of {@link TemporalQuery}. + * These queries are primarily used as optimizations, allowing the internals + * of other objects to be extracted effectively. Note that application code + * can also use the {@code from(TemporalAccessor)} method on most temporal + * objects as a method reference matching the query interface, such as + * {@code LocalDate::from} and {@code ZoneId::from}. + *
+ * There are two equivalent ways of using a {@code TemporalQuery}. + * The first is to invoke the method on the interface directly. + * The second is to use {@link TemporalAccessor#query(TemporalQuery)}: + *
+ * // these two lines are equivalent, but the second approach is recommended + * dateTime = query.queryFrom(dateTime); + * dateTime = dateTime.query(query); + *+ * It is recommended to use the second approach, {@code query(TemporalQuery)}, + * as it is a lot clearer to read in code. + * + *
+ * This queries a {@code TemporalAccessor} for the zone. + * The zone is only returned if the date-time conceptually contains a {@code ZoneId}. + * It will not be returned if the date-time only conceptually has an {@code ZoneOffset}. + * Thus a {@link java.time.ZonedDateTime ZonedDateTime} will return the result of + * {@code getZone()}, but an {@link java.time.temporal.OffsetDateTime OffsetDateTime} will + * return null. + *
+ * In most cases, applications should use {@link #ZONE} as this query is too strict. + *
+ * The result from JDK classes implementing {@code TemporalAccessor} is as follows:
+ * This queries a {@code TemporalAccessor} for the chronology.
+ * If the target {@code TemporalAccessor} represents a date, or part of a date,
+ * then it should return the chronology that the date is expressed in.
+ * As a result of this definition, objects only representing time, such as
+ * {@code LocalTime}, will return null.
+ *
+ * The result from JDK classes implementing {@code TemporalAccessor} is as follows:
+ * The method {@link Chrono#from(TemporalAccessor)} can be used as a
+ * {@code TemporalQuery} via a method reference, {@code Chrono::from}.
+ * That method is equivalent to this query, except that it throws an
+ * exception if a chronology cannot be obtained.
+ * @return a Chrono, may be null
+ */
+ public static final TemporalQuery
+ * This queries a {@code TemporalAccessor} for the time precision.
+ * If the target {@code TemporalAccessor} represents a consistent or complete date-time,
+ * date or time then this must return the smallest precision actually supported.
+ * Note that fields such as {@code NANO_OF_DAY} and {@code NANO_OF_SECOND}
+ * are defined to always return ignoring the precision, thus this is the only
+ * way to find the actual smallest supported unit.
+ * For example, were {@code GregorianCalendar} to implement {@code TemporalAccessor}
+ * it would return a precision of {@code MILLIS}.
+ *
+ * The result from JDK classes implementing {@code TemporalAccessor} is as follows:
+ * This queries a {@code TemporalAccessor} for the zone.
+ * It first tries to obtain the zone, using {@link #zoneId()}.
+ * If that is not found it tries to obtain the {@link #offset()}.
+ *
+ * In most cases, applications should use this query rather than {@code #zoneId()}.
+ *
+ * This query examines the {@link java.time.temporal.ChronoField#OFFSET_SECONDS offset-seconds}
+ * field and uses it to create a {@code ZoneOffset}.
+ *
+ * The method {@link ZoneId#from(TemporalAccessor)} can be used as a
+ * {@code TemporalQuery} via a method reference, {@code ZoneId::from}.
+ * That method is equivalent to this query, except that it throws an
+ * exception if a zone cannot be obtained.
+ * @return a ZoneId, may be null
+ */
+ public static final TemporalQuery
+ * This queries a {@code TemporalAccessor} for the offset.
+ *
+ * This query examines the {@link java.time.temporal.ChronoField#OFFSET_SECONDS offset-seconds}
+ * field and uses it to create a {@code ZoneOffset}.
+ *
+ * The method {@link ZoneOffset#from(TemporalAccessor)} can be used as a
+ * {@code TemporalQuery} via a method reference, {@code ZoneOffset::from}.
+ * That method is equivalent to this query, except that it throws an
+ * exception if an offset cannot be obtained.
+ * @return a ZoneOffset, may be null
+ */
+ public static final TemporalQuery
+ * {@code LocalDate} returns null
+ * {@code LocalTime} returns null
+ * {@code LocalDateTime} returns null
+ * {@code ZonedDateTime} returns the associated zone
+ * {@code OffsetDate} returns null
+ * {@code OffsetTime} returns null
+ * {@code OffsetDateTime} returns null
+ * {@code ChronoLocalDate} returns null
+ * {@code ChronoLocalDateTime} returns null
+ * {@code ChronoZonedDateTime} returns the associated zone
+ * {@code Era} returns null
+ * {@code DayOfWeek} returns null
+ * {@code Month} returns null
+ * {@code Year} returns null
+ * {@code YearMonth} returns null
+ * {@code MonthDay} returns null
+ * {@code ZoneOffset} returns null
+ * {@code Instant} returns null
+ * @return a ZoneId, may be null
+ */
+ public static final TemporalQuery
+ * {@code LocalDate} returns {@code ISOChrono.INSTANCE}
+ * {@code LocalTime} returns null (does not represent a date)
+ * {@code LocalDateTime} returns {@code ISOChrono.INSTANCE}
+ * {@code ZonedDateTime} returns {@code ISOChrono.INSTANCE}
+ * {@code OffsetDate} returns {@code ISOChrono.INSTANCE}
+ * {@code OffsetTime} returns null (does not represent a date)
+ * {@code OffsetDateTime} returns {@code ISOChrono.INSTANCE}
+ * {@code ChronoLocalDate} returns the associated chronology
+ * {@code ChronoLocalDateTime} returns the associated chronology
+ * {@code ChronoZonedDateTime} returns the associated chronology
+ * {@code Era} returns the associated chronology
+ * {@code DayOfWeek} returns null (shared across chronologies)
+ * {@code Month} returns {@code ISOChrono.INSTANCE}
+ * {@code Year} returns {@code ISOChrono.INSTANCE}
+ * {@code YearMonth} returns {@code ISOChrono.INSTANCE}
+ * {@code MonthDay} returns null {@code ISOChrono.INSTANCE}
+ * {@code ZoneOffset} returns null (does not represent a date)
+ * {@code Instant} returns null (does not represent a date)
+ *
+ * {@code LocalDate} returns {@code DAYS}
+ * {@code LocalTime} returns {@code NANOS}
+ * {@code LocalDateTime} returns {@code NANOS}
+ * {@code ZonedDateTime} returns {@code NANOS}
+ * {@code OffsetDate} returns {@code DAYS}
+ * {@code OffsetTime} returns {@code NANOS}
+ * {@code OffsetDateTime} returns {@code NANOS}
+ * {@code ChronoLocalDate} returns {@code DAYS}
+ * {@code ChronoLocalDateTime} returns {@code NANOS}
+ * {@code ChronoZonedDateTime} returns {@code NANOS}
+ * {@code Era} returns {@code ERAS}
+ * {@code DayOfWeek} returns {@code DAYS}
+ * {@code Month} returns {@code MONTHS}
+ * {@code Year} returns {@code YEARS}
+ * {@code YearMonth} returns {@code MONTHS}
+ * {@code MonthDay} returns null (does not represent a complete date or time)
+ * {@code ZoneOffset} returns null (does not represent a date or time)
+ * {@code Instant} returns {@code NANOS}
+ * @return a ChronoUnit, may be null
+ */
+ public static final TemporalQuery